The present invention is in the field of diagnostics and is particularly concerned with lipid assays and an improved human lipids control serum possessing higher than normal concentrations of lipids, such as triglycerides, cholesterol, phospholipids, total lipids, glycerol and non-esterified fatty acids, all obtained from a lipid rich fraction of human plasma. The present invention involves a normal human serum carrier to which has been added a human plasma fraction such as Cohn Fraction III-2,1, rich in lipids to give an all human control serum possessing elevated concentrations of lipids.
Lyophilized elevated lipid control sera comprising human serum selected from individuals known to possess elevated concentrations of lipids for use as a control in assays for lipids is known and currently available..sup.1 However, such a sera is inconvenient and expensive to obtain and not as readily available as desired since it depends solely upon the availability of and accessability to individuals possessing elevated concentrations of lipids. The present invention overcomes these disadvantages. FNT .sup.1 e.g., Elevated Lipids Control Serum, Lederle Diagnostics, American Cyanamid Company, Pearl River, New York.
It is known that certain fractions of human plasma are rich in lipids such as Cohn Fraction III, and similar fractions, Cohn, E. J. et al., J. Amer. Chem. Soc. Vol. 68, pp. 459-475 (March, 1946). Cohn Fraction III is obtained in the processing of whole blood to plasma as a precipitate formed during alcoholic extraction, Cohn, et al. supra. The lipid constituents of Cohn Fraction III vary from batch to batch but fractions having arbitrarily set minimum values for constituents of importance to the establishment of a control have been determined to be satisfactory as starting materials.
U.S. Pat. No. 3,751,381 discloses a non-lyophilized serum lipid assay standard containing the lipid rich Cohn Fraction III in conjunction with bovine serum albumin to enhance the stability of the protein constituents in the serum and a yellow dye to give a color more closely approximating that of the lipid rich portion of fresh serum. The U.S. Pat. No. 3,751,381 patent points out that the reference standard disclosed therein is not suitable for reduction to the lyophilized state as it has been found that lyophilization greatly reduces the quality of the standard which is manifested by reduced recoverable lipoproteins and by increased turbidity of the reconstituted material.
U.S. Pat. No. 3,260,648 discloses a lyophilized standard composition to be reconstituted when needed for use in the determination of total cholesterol levels in human blood plasma comprising lyophilized, processed human blood plasma, a predetermined quantity of total cholesterol in the free form or as an ester derived from unknown sources and a necessary solubilizing agent to help dissolve the cholesterol upon reconstitution.
U.S. Pat. No. 3,682,835 discloses an aqueous blood serum control standard for use in the analysis of blood serum comprising defibrinated plasma which has been treated with a strong acid cation exchange resin to reduce the alkali and alkaline earth metal cation level and from which the lipoprotein component has been removed by extraction with a fat solvent. Cholesterol is said to be illustrative of a blood serum component which can be added to the aqueous liquid for use as a control.
U.S. Pat. No. 3,764,556 discloses a lipid control made up of triglyceride and cholesterol rich fractions from chicken eggs and outdated human plasma, and certain fractions of horse or bovine sera.
None of the above art is concerned with an all human elevated lipid control serum as disclosed herein.